Refrigeration apparatus

ABSTRACT

A refrigeration apparatus having means defining a compartment which at least at times is refrigerated to a below-freezing temperature. Air is returned from this compartment to a fin-andtube evaporator by firstly conducting the air over the tube end turns of the evaporator and then through the passages defined by the evaporator fins to be refrigerated by heat exchange relationship therewith. The compartment may comprise a convertible compartment which, at times, is maintained at an above-freezing temperature and at times is maintained at a belowfreezing temperature. The apparatus may further include a refrigerator compartment and a freezer compartment with the air being returned to different portions of the evaporator from the different compartments for improved operation of the refrigeration apparatus.

REFRIGERATION APPARATUS Inventors: James P. Laughlin, Evansville;Primary Emmmwmwmiam wyc Attorney-James S. Ncttleton cl n1.

Wilfred W. McCullough, Evansville, both of lnd.

ABSTRACT [73] Assignee: Whirlpool Corporation, Benton Harbor, Mich.

Dec. 1, 1971 A refrigeration apparatus having means defining a [22] Fild; compartment which at least at times is refrigerated to abelow-freezing temperature. Air is returned from this Appl. No.: 203,555

compartment to a fin-and-tube evaporator by firstly conducting the airover the tube end turns of the evapo rator and then through the passagesdefined by the evaporator fins to be refrigerated by heat exchange relationship therewith. The compartment may comprise 664 2M 7 H M 1 M.2 2MM "2 9 1"" 4 n" I. 2 m m r. na ue nns L m .w U.mF Hum 555 [[21 aconvertible compartment which, at times, is main- 5 References Citedtained at an above-freezing temperature and at times is UNITED STATESPATENTS maintained at a below-freezing temperature. The appa- L ratusmay further include a refrigerator compartment when and a freezercompartment with the air being returned 62/426 62/426 to differentportions of the evaporator from the differ- 62/426 ent compartments forimproved operation of the refrig- 62/426 eration apparatus.

10 Claims, Drawing Figures 897 2/1935 Higgins 238 2/1939 Kraekowizer....939 10/1942 Swanson 176 6/1943 Ashley...... 024 8/1962 Jacobs 677 4/1968Bright i 1 a a i i 9 i a i v Q a i Pmmmw 1m:

sum 2 or 2 DEJIIGIIIE] U REFRIGERATION APPARATUS BACKGROUND OF THEINVENTION 1. Field of the Invention This invention relates torefrigeration apparatus and in particular to such apparatus having oneor more compartments to be refrigerated by means of a forced flow of aircirculated in heat exchange relationship with an evaporator.

2. Description of the Prior Art In the Sigl et al. US. Letters Pat. No.3,411,312, owned by the assignee hereof, a refrigerator with aconvertible compartment is shown and described as utilizing a forced airsystem wherein the air delivered to the different compartments is passedin heat exchange relationship with a fin and tube evaporator. In theapparatus thereof, the air is returned from the different compartmentsto a common inlet portion of the evaporator after being passed in heatexchange relationship with an accumulator.

In the Mann et al. U.S. S. Letters Pat. No. 3,027,732, a refrigeratingapparatus is shown to comprise a refrigerator-freezer apparatus whereinair is circulated in heat exchange relationship with an evaporator tothe refrigerator and freezer compartments. As shown in FIG. of thatpatent, the air from the refrigerator compartment is passed over one endof the evaporator having widely spaced fins and then successivelythrough second and third portions of the evaporator having normallyclosely spaced fins. The air from the freezer compartment is deliveredin heat exchange relationship only with the third portion of theevaporator.

Additional patents which show refrigeration apparatus related to theabove discussed apparatuses are those ofSolley, .lr. U.S. Pat. No;3,111,817;Schumacher US. Pat. No. 3,126,717; and Frohbieter US. Pat. No.3,389,575, which is also owned by the assignee hereof.

SUMMARY OF THE INVENTION The present invention comprehends an improvedrefrigeration apparatus wherein air from a freezer compartment isfirstly circulated in heat exchange relationship with the end turns ofthe evaporator prior to the delivery thereof to the normal flow paththrough the evaporator as defined by the fins. In the specificembodiment of the invention disclosed herein, the freezer compartment isa convertible compartment which, at times, may be maintained atabove-freezing temperatures and at other times at below-freezingtemperatures.

The inventio further comprehends the provision of means cooperating withat least one of the fins at one side of the evaporator to form a wallmeans defining a flow passage for conducting the air from theconvertible compartment over the end turns of the evaporator beforedelivery thereof to a plurality of normal flow pathsdefined by the fins.The air delivered from the end turn flow path is delivered to a chamberin which the accumulator is located at the inlet portion of theevaporator. The air from the refrigerator compartment may be deliveredto the same chamber at the opposite side of the evaporator for flowprimarily through a portion of the plurality of the paths defined by thefins different from the portion of the plurality of paths defined by thefins through which the air from the convertible compartment flows. Thus,it has been found that any tendency to frost over at the inlet to theevaporator in the paths through which the air from the refrigeratornormally flows will cause this air to tend to flow through the pathsthrough which the air from the convertible compartment normally flows.As the air from the convertible compartment is efiectively dehumidified,these latter paths are effectively maintained open for extendedoperation of the apparatus before defrosting thereof is required. Theinvention further comprehends returning the freezer compartment air to alocation in the paths defined by the fins spaced from the inlet portionof the evaporator whereby frosting as a result of the introduction ofthe low temperature air into the air returned from the refrigeratorcompartment and convertible compartment (particularly when theconvertible compartment is operated as a refrigerator compartment) iseffectively avoided.

The invention comprehends that approximately 20 percent of the heatexchange surface of the evaporator be located in the end turn flow pathfrom the convertible compartment for effectively optimumdehumidification of the air prior to the delivery thereof to the normalheat exchange paths defined by the fins.

The air flow control means of the present invention is extremely simpleand economical of construction while yet providing the highly improvedoperation of the apparatus as discussed above.

BRIEF DESCRIPTION OF THE DRAWING Other features and advantages of theinvention will be apparent from the following description taken inconnection with the accompanying drawing wherein:

FIG. 1 is a front elevation of a refrigeration apparatus embodying theinvention, with the doors to the different compartments omitted;

FIG. 2 is a side elevation with a portion thereof shown in verticalsection;

FIG. 3 is a fragmentary enlarged vertical section taken substantiallyalong the line 3-3 of FIG. 2;

FIG. 4 is a fragmentary section generally similar to that of FIG. 3 butillustrating the air flow upon a partial frosting over of the inletportion of the evaporator by the refrigerator air;

FIG. 5 is an enlarged fragmentary section taken substantially along theline 5-5 of FIG. 3; and

FIG. 6 is an enlarged fragmentary section taken sub stantially along theline 6-6 of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the exemplary embodiment ofthe invention as disclosed in the drawing, a refrigeration apparatusgenerally designated 10 is shown to include a cabinet 11 defining aplurality of compartments to be refrigerated including an above-freezingtemperature refrigerator compartment 12, a below-freezing temperaturefreezer compartment 13, and a convertible compartment 14 arranged to beselectively alternatively refrigerated to either an above-freezingtemperature or a belowfreezing temperature so that compartment 14 mayselectively comprise a second refrigerator compartment or a secondfreezer compartment as desired. As discussed above, one such convertiblecompartment rcfrigeration apparatus is shown in the Sigl et al. US. Pat.No. 3,411,312 owned by the assignee hereof.

As shown in FIGS. 1 and 2 of the drawing, the refrigeration of thecompartments is effected by the flow of refrigerated air therethrough bya suitable air moving means, such as fan 15. The circulated air isrefrigerated as a result of being passed in heat exchange relationshipwith a fin and tube evaporator 16 which is suitably refrigerated byconventional means, such as apparatus 17 including a conventionalcompressor 18, condenser 19, refrigerant supply duct 20, and refrigerantreturn duct 21. The refrigeration apparatus functions in theconventional manner to provide refrigerated refrigerant fluid to theserpentine tube portion 22 of the evaporator and an accumulator, orheader, 23, is provided between portion 22 and the return duct 21 tocollect any liquid refrigerant which may have passed through tubeportion 22 of the evaporator. As illustrated in FIG. 3, evaporator 16 isfurther provided with a plurality of heat conducting fins 24 which arein heat exchange relationship with the tube 22 and cooperatively definea plurality of paths 25 through which the air is flowed to have thedesired heat exchange relationship with the evaporator structure. Theevaporator 16 further includes end plates 52 and 53 which support theevaporator and are used to mount the evaporator within freezercompartment.

In the illustrated embodiment, evaporator 16 comprises a verticalevaporator disposed behind a rear panel 26 of freezer compartment 13 sothat the air flow paths extend vertically upwardly from a lowermostinlet portion 27 of the evaporator to an uppermost outlet portion 28thereof. Fan is disposed upwardly of the. outlet portion 28, as shown inFIG. 3, so as to draw the air through the evaporator paths and dischargeit through suitable air ducts 29 and 30 to the different compartments.As illustrated in FIG. 1, air is delivered from duct 29 through a grilloutlet 31 to the refrigerator compartment 12, and through a grill outlet32 to the convertible compartment 14. The air is delivered from duct 30through a grill outlet 33 to the freezer compartment 13.

As disclosed in the Sigl, et al. patent, in such a multiple-compartmentrefrigeration apparatus, suitable damper controls may be provided forregulating the air flow so as to provide selectively the desiredtemperature conditions in the different compartments, and morespecifically herein, controls 34 are provided to include means forpermitting control of the temperature conditions in compartment 14 sothat the compartment may be operated convertibly either as a freezercompartment or as a refrigerator compartment as discussed above. As willbe obvious to those skilled in the art, any suitable means for effectingthis temperature control of the different compartments may be em ployedwithin the scope of the invention. The present invention is concernedprimarily with the control of the flow of the air back to and throughthe evaporator so as to provide an improved high efficiency operation ofthe apparatus.

More specifically, as shown in FIGS. 1 and 3, the air from refrigeratorcompartment 12 is delivered to the chamber 35 below the inlet portion 27of the evaporator behind the freezer chamber rear panel 26 and forwardlyof the rear cabinet wall 36 through an opening 37 in an upright dividerwall 38 of the cabinet. Air is returned from convertible compartment 14through a grill outlet 39 in the rear wall 40 of compartment 14 at oneside of delivery duct 29 to flow downwardly therefrom through a flowpassage 41 rearwardly of rear walls 40 and 26. Outlet 39 communicateswith flow passage 41 through an opening 42 in a horizontal divider wall43 defining the top of freezer compartment 13 and the bottom ofconvertible compartment 14.

Flow passage 41 is arranged to conduct the returning air fromconvertible compartment 14 in heat exchange relationship with the endturns 44 of the evaporator 16 prior to the delivery thereof to thevertical flow paths 25 between the fins. To this end, the passage 41 isdefined by the lefthand side wall 45 of cabinet 11, the rear wall 36 ofcabinet 11, the panel 26 of compartment 13, a partition wall member 47and an air divider 46 which cooperates with lefthand fins 24a and 24b ofthe evaporator. As shown in FIG. 5, the air divider member 46 maycomprise a formed sheet element having a flat end 48 secured to the rearcabinet wall 26 and a V-section portion 49 extending into the space 250defined by the fin 24a and the rightwardly adjacent fin 24b.

As shown in FIG. 3, partition wall 47 extends downwardly from thehorizontal cabinet wall 43 to the inlet portion 27 of the evaporator. Aportion 54 of divider wall 47 extends between fins 24a and 24b andterminates on the top of tube 22 to assure that air in passage 41 passesfirst over end turns 44 then through passages 25. As shown in FIG. 6,the partition wall 47 is a generally rectangular member formed of moldedpolystyrene foam or other similar material. Inasmuch as partition wall47 closes off space 250 between fins 24a and 2412, cover 26 seals acrossthe same fins at their front face and the V-section portion 49 of airdivider 46 seals the same fins at their rear face, fins 24a and 24benclose a non air flow space 25a which effectively forms an extension ofpartition 47.

Thus, as shown in FIG. 3, flow passage 41 conducts air from convertiblecompartment 14 in heat exchange relationship with the lefthand end turns44, end plate 53 and fin 24a of the evaporator downwardly to chamber 35to be further in heat exchange relationship with the accumulator 23before turning and flowing upwardly through the lefthand paths 25 of theevaporator. As a result, humidity in the air returning from theconvertible compartment is effectively removed by the heat transferassociation thereof with the end turns 44, end plate 53 and fin 24athereby effectively avoiding frosting of the lower end of the flow paths25 through which this air is flowed to effect the further refrigerationthereof.

In the illustrated embodiment, approximately 20 percent of the heatexchange surface of the evaporator is provided in the flow passage 41and approximately percent thereof is provided at the flow paths 25.

As best seen in FIG. 1, the air returning to the evaporator from thefreezer compartment 13 flows through the grill outlet 50 in the rearwall 26 so as to enter the evaporator space at a location 51 spacedupwardly from the entrance portion 27 thereby effectively preventingfrosting and snow at the entrance portion which could occur if therelatively cold freezer air were delivered to entrance 27 to mix thereatwith the moist air from the refrigerator compartment 12.

It has been found that in the use of such a refrigeration apparatushaving a convertible freezer-refrigerator compartment, the temperature,humidity and the flow rate through the evaporator of the air from theconvertible compartment may vary over a wide range. When compartment 14is operated by the control 34 to comprise a refrigerator compartment atabove-freezing temperature, the air returned to the evaporator therefromhas a relatively high humidity. At this time, the

flow rate of the air is made relatively low, i.e., approximately timesless than when the compartment is operated as a freezer compartment.

As illustrated in FIGS. 3 and 4, in the normal operation of theapparatus, relatively moist air from the re frigerator compartment 12flows from passage 37 upwardly through the righthand flow paths 25defined by the spaced fins 24. In flowing from passage 37 to the inletportion 27 of the evaporator, this air is firstly caused to pass overthe accumulator, or header, 23 so as to effect at least a partialmoisture removal from the air as a result of the relatively lowtemperature of the accumulator.

When the convertible compartment is being operated as a refrigeratorcompartment, the relatively low flow rate permits the air from passage41 to flow primarily through the lefthand paths 25 as discussed above.When the compartment 14 is operated as a freezer compartment to have arelatively high flow rate, the flow through the paths 25 is neverthelessmaintained primarily through the lefthand paths. This desirableoperation is automatically effected by the control of the frosting ofthe evaporator at the entrance portion 27 effected by the pre-drying ofthe air from compartment 14 as a result of its heat exchangerelationship with the evaporator end turns 44, end plate 53 and fin 24aprior to the delivery thereof to the entrance portion 27 of theevaporator. There is always a tendency for frost buildup at the entranceportion to the evaporator at the righthand flow paths, as shown in FIGS.3 and 4, and as such buildup occurs the air from compartment 12 tends toflow more leftwardly toward the lefthand flow paths which are maintainedrelatively open as a result of the moisture removed from the air frompassage 41 before the delivery thereof to the lefthand flow paths.Resultingly, as the righthand paths become progressively more blocked,the flow of refrigerator compartment air is caused to shift away fromblocked air paths to the relatively clear lefthand air paths therebysubstantially extending the period of operation of the apparatus beforedefrosting of the evaporator is required. Thus, while the flow rate ofthe air stream entering the evaporator at 27 from passage 41 varies overa 10 to 1 range, the paths the air streams follow through the evaporatorremain essentially unchanged even though the humidity of the air streamleaving convertible compartment l4 varies greatly.

A baffle 55 in the form of a molded polystyrene foam block is providedbetween the right side of evaporator 16 and wall 38 to prevent air fromcompartment 12 from bypassing vertical paths 25 through the evaporator.A defrost heater, not shown, is provided to periodically heat theevaporator to melt any frost accumulated thereon. One such suitableheater is shown and described in the copending application of RaymondTobey, Ser. No. 141,478, filed May 10, 1971 and assigned to the assigneeof this application.

The improved operation of the .air refrigeration means of the presentinvention is obtained with effec tively minimum cost by properproportioning of the evaporator air flow paths by the simple addition ofthe partition wall means 47 and the air divider means 46 to theconventional evaporator structure. The invention permits the selectiveuse of the convertible compartment 14 without adversely affecting theair flow conditions in the evaporator or the temperature conditions 7 incompartments l2 and 13, but rather to the contrary,

the convertible compartment return air flow in conjunction with theproper proportioning of the air fiow through vertical paths 25 providesa desirable extended refrigerating operation of the apparatus betweendefrosting operations.

The foregoing disclosure of specific embodiments is illustrative of thebroad inventive concepts comprehended by the invention.

I-Iaving described the invention, the embodiments of the invention inwhich an exclusive property or privilege is claimed are defined asfollows:

1. In a forced air refrigeration apparatus having means defining acompartment which may have selectively different humidity conditionsincluding a high humidity condition, a refrigeration means including anevaporator having a serpentine tube portion defining a plurality of endturns and a plurality of fins defining a plurality of paths for flow ofair to be refrigerated in heat transfer association therewith from aninlet portion at one end of the evaporator to an outlet portion at theopposite end of the evaporator, and means for circulating air from saidevaporator outlet portion through said compartment and back to saidevaporator for cooling said compartment to a below-freezing temperature,the improvement comprising means for causing only low humidity air to becirculated in heat transfer association with said evaporator finscomprising means for conducting the air from said compartmentsequentially in heat transfer association with said end turns and thento said paths defined by said fins, the amount of heat transfer surfaceof said end turns contacted by said conducted air being preselected toeffect dehumidification of high humidity compartment air to convert saidair to low humidity air prior to the conduction thereof into said paths.

2. The refrigeration apparatus of claim 1 wherein said means forconducting the air from said compartment comprises a wall member and adivider member cooperating with at least one of said fins to define aboundary of the flow path for the air over said end turns.

3. The refrigeration apparatus of claim 1 wherein said means forconducting the air from said compartment comprises a wall member and adivider member cooperating with at least one of said fins to define aboundary of the flow path for the air over said end turns, said endturns associated with said flow path comprising approximately 20 percentof the heat exchange means of the evaporator.

41. The refrigeration apparatus of claim 1 including an accumulatorupstream of the inlet portion of the evaporator, said means forconducting the air from said compartment being constructed to conductthe air firstly in heat exchange relationship with the end turns andthen in heat exchange relationship with said accumulator prior to flowthrough said paths defined by said fins.

5. in a forced air refrigerator-freezer apparatus having means defininga below-freezing compartment, an above-freezing refrigeratorcompartment, and a compartment convertible selectively to be anabovefreezing refrigerator compartment or a below-freezing freezercompartment, refrigeration means including an evaporator having aserpentine tube portion defining a plurality of end turns and aplurality of fins defining a plurality of paths for flow of air to berefrigerated in heat transfer association therewith from an inletportion at one end of the evaporator to an outlet portion at theopposite end of the evaporator, and means for circulating air from saidevaporator outlet portion.

through said compartments and back to said evaporator, the improvementcomprising:

means for conducting the air from said convertible compartmentsequentially in heat transfer association with said end turns and thento said paths defined by said fins.

6. The refrigerator-freezer apparatus of claim wherein said circulatingmeans causes the air from said refrigerator compartment to flowprimarily through a portion of said plurality of paths different fromthe paths through which the air from said convertible compartment isflowed.

7. The refrigerator-freezer apparatus of claim 5 wherein saidcirculating means includes means for delivering the air from saidfreezer compartment to a portion of said paths spaced from said inletportion of the evaporator.

8. The refrigerator-freezer apparatus of claim 5 wherein saidcirculating means causes the air from said refrigerator compartment toflow primarily through a portion of said plurality of paths differentfrom the paths through which the air from said convertible compartmentis flowed, and said circulating means includes means for delivering theair from said freezer compartment to substantially all of said paths ata location spaced from said inlet portions of the evaporator.

9. The refrigerator-freezer apparatus of claim 5 wherein said evaporatoris a vertical evaporator and said paths defined by said fins extendvertically with said inlet portion of the evaporator lowermost.

10. The refrigerator-freezer apparatus of claim 5 wherein saidevaporator is located in a compartment defined by the rear wall of thebelow-freezing compartment and an evaporator cover, said means forconducting air from said convertible compartment comprising:

a passage within said evaporator compartment defined by said rear wall,a side wall of the evaporator compartment, a partition wall bridging thespace between said rear wall and said cover extending from the top edgeof the evaporator compartment to the outlet portion of the evaporator,and an air divider member cooperating with at least one of saidevaporator fins to form an extension of said partition wall to the inletportion of said evaporator to thereby separate air flowing from saidconvertible compartment in heat transfer association with said end turnsand air flowing in heat transfer association with said plurality ofpaths.

1. In a forced air refrigeration apparatus having means defining acompartment which may have selectively different humidity conditionsincluding a high humidity condition, a refrigeration means including anevaporator having a serpentine tube portion defining a plurality of endturns and a plurality of fins defining a plurality of paths for flow ofair to be refrigerated in heat transfer association therewith from aninlet portion at one end of the evaporator to an outlet portion at theopposite end of the evaporator, and means for circulating air from saidevaporator outlet portion through said compartment and back to saidevaporator for cooling said compartment to a below-freezing temperature,the improvement comprising means for causing only low humidiTy air to becirculated in heat transfer association with said evaporator finscomprising means for conducting the air from said compartmentsequentially in heat transfer association with said end turns and thento said paths defined by said fins, the amount of heat transfer surfaceof said end turns contacted by said conducted air being preselected toeffect dehumidification of high humidity compartment air to convert saidair to low humidity air prior to the conduction thereof into said paths.2. The refrigeration apparatus of claim 1 wherein said means forconducting the air from said compartment comprises a wall member and adivider member cooperating with at least one of said fins to define aboundary of the flow path for the air over said end turns.
 3. Therefrigeration apparatus of claim 1 wherein said means for conducting theair from said compartment comprises a wall member and a divider membercooperating with at least one of said fins to define a boundary of theflow path for the air over said end turns, said end turns associatedwith said flow path comprising approximately 20 percent of the heatexchange means of the evaporator.
 4. The refrigeration apparatus ofclaim 1 including an accumulator upstream of the inlet portion of theevaporator, said means for conducting the air from said compartmentbeing constructed to conduct the air firstly in heat exchangerelationship with the end turns and then in heat exchange relationshipwith said accumulator prior to flow through said paths defined by saidfins.
 5. In a forced air refrigerator-freezer apparatus having meansdefining a below-freezing compartment, an above-freezing refrigeratorcompartment, and a compartment convertible selectively to be anabove-freezing refrigerator compartment or a below-freezing freezercompartment, refrigeration means including an evaporator having aserpentine tube portion defining a plurality of end turns and aplurality of fins defining a plurality of paths for flow of air to berefrigerated in heat transfer association therewith from an inletportion at one end of the evaporator to an outlet portion at theopposite end of the evaporator, and means for circulating air from saidevaporator outlet portion through said compartments and back to saidevaporator, the improvement comprising: means for conducting the airfron said convertible compartment sequentially in heat transferassociation with said end turns and then to said paths defined by saidfins.
 6. The refrigerator-freezer apparatus of claim 5 wherein saidcirculating means causes the air from said refrigerator compartment toflow primarily through a portion of said plurality of paths differentfrom the paths through which the air from said convertible compartmentis flowed.
 7. The refrigerator-freezer apparatus of claim 5 wherein saidcirculating means includes means for delivering the air from saidfreezer compartment to a portion of said paths spaced from said inletportion of the evaporator.
 8. The refrigerator-freezer apparatus ofclaim 5 wherein said circulating means causes the air from saidrefrigerator compartment to flow primarily through a portion of saidplurality of paths different from the paths through which the air fromsaid convertible compartment is flowed, and said circulating meansincludes means for delivering the air from said freezer compartment tosubstantially all of said paths at a location spaced from said inletportions of the evaporator.
 9. The refrigerator-freezer apparatus ofclaim 5 wherein said evaporator is a vertical evaporator and said pathsdefined by said fins extend vertically with said inlet portion of theevaporator lowermost.
 10. The refrigerator-freezer apparatus of claim 5wherein said evaporator is located in a compartment defined by the rearwall of the below-freezing compartment and an evaporator cover, saidmeans for conducting air from said convertible compartment comprising: apassage within said evaporator compartment defined bY said rear wall, aside wall of the evaporator compartment, a partition wall bridging thespace between said rear wall and said cover extending from the top edgeof the evaporator compartment to the outlet portion of the evaporator,and an air divider member cooperating with at least one of saidevaporator fins to form an extension of said partition wall to the inletportion of said evaporator to thereby separate air flowing from saidconvertible compartment in heat transfer association with said end turnsand air flowing in heat transfer association with said plurality ofpaths.